Why does Ableton say my Tracks are corrupt or unlicensed?

I was attempting to DJ. I went into my folder containing all of my MP3s (which were purchased from beatport) only to find that Live says they are "corrupt or not licensed." out of over 100 tracks maybe 4 work. I also have live on my desktop, The songs work fine there. They also work fine in other programs on my laptop. Whats going on?